"It was great," he told E! News. "She did a really great job, and I was really proud of her."

Derek, who jokingly offered his sister a $10 bribe before she judged him and his partner Amber Riley, added that he would have understood if she had offered some harsh critiques.

"Julianne and I are so honest with each other I understand what she meant [on the show]," he said. "She said she kind of wanted there to be something she could say [to criticize the performance] so that she wouldn't seem biased. But I know that if she wanted to she would have taken much pleasure in doing that."